In liquid crystal display devices, a pixel circuit is arranged for each pixel so as to display the corresponding pixel. Each pixel circuit is provided therein with a pixel transistor and a pixel capacitor. A liquid crystal display device is provided therein with a gate drive circuit for gate driving of the pixel transistors in the pixel circuits, i.e., for controlling the ON/OFF of the pixel transistors. When a pixel transistor is turned on, a data voltage will charge the respective pixel capacitor through the pixel transistor. The charged pixel capacitor can control the output of corresponding optical signals.
Generally speaking, the gate drive circuit is provided with a plurality of output ports with each output port being connected with a gate driving line of a pixel row, and the gate driving line being connected with the gates of the pixel transistors of all the pixel circuits in the pixel row. The gate drive circuit outputs a drive voltage to a connected gate driving line through some output port, so as to control the turn-on and turn-off of the pixel transistors of all the pixel circuits in the corresponding pixel row. When the drive voltage is a high level transistor turn-on voltage VGH, the pixel transistor is turned on, and when the drive voltage is a low level transistor turn-off voltage VGL, the pixel transistor is turned off.